According to the American Journal of Infection Control, more than 164 million school days are missed annually in U.S. public schools due to the spread of infectious diseases. An astonishing three million of those school days are lost as a result of acute conjunctivitis, also known as "pink eye."

The American Academy of Ophthalmology wants to teach parents and educators how to prevent the spread of pink eye in the classroom.

"Pink eye is all too common amongst children; it is one of the most common conditions I treat," says Lee Duffner, MD, ophthalmologist and clinical correspondent for the Academy. "The only way to really prevent pink eye from spreading is to practice good hygiene."

What is conjunctivitis?

Conjunctivitis is the term used to describe swelling of the conjunctiva - the thin, filmy membrane that covers the inside of your eyelids and the white part of the eye, known as the sclera. There are three forms of conjunctivitis: viral, bacterial and allergic.

Viral conjunctivitis, the most common form of pink eye, is caused by the same virus that causes the common cold. Just as a cold must run its course, so must this form of pink eye. It is also very contagious.

Bacterial conjunctivitis is a highly contagious form of pink eye, caused by bacterial infections. This type of conjunctivitis usually causes a red eye with a lot of pus.

Allergic conjunctivitis is a form of conjunctivitis that is caused by the body's reaction to an allergen or irritant. It is not contagious. This type of conjunctivitis is usually associated with redness in the white of the eye or inner eyelid.

How do you get pink eye and how do you prevent it?

Conjunctivitis, whether bacterial or viral, can be quite contagious. Children are usually most susceptible to getting the condition from bacteria or viruses because they are in close contact with so many others in schools or daycare centers. Some of the most common ways to get the contagious form of pink eye:

Reusing handkerchiefs and towels when wiping your face and eyes

Forgetting to wash hands often

Frequently touching eyes

Using old cosmetics, and/or sharing them with other people

Not cleaning contact lenses properly

Prevention

Practicing good hygiene can help prevent the spread of conjunctivitis. If a child is infected, make sure to do the following to help prevent the spread of the illness:

Encourage children to wash their hands often

Tell them to avoid touching their eyes

Discourage the reusing of towels, washcloths, handkerchiefs and tissues to wipe their face and eyes

Change their pillowcase frequently

Treatment

With viral conjunctivitis, symptoms can last from one to two weeks and then will disappear on their own.

Allergic conjunctivitis treatment often includes applying cool compresses to the eyes and taking antihistamines.

Home care tips

A compress applied to closed eyelids can relieve some of the discomfort of pink eye. To make a compress, soak in water then wring out a clean, lint-free cloth. If a child has conjunctivitis in one eye only, don't use the same cloth on both eyes in order to avoid spreading the infection from one eye to the other.

If a child has bacterial or viral conjunctivitis, a warm compress is usually best. If their eyes are irritated by allergic conjunctivitis, try a cool water compress. Over-the-counter lubricating eye drops - artificial tears - may also provide relief from pink eye symptoms.

If these symptoms persist, be sure take your child to see an ophthalmologist to receive proper care.

To find out more information on pink eye and other eye conditions and diseases, visit www.geteyesmart.org.